Digital camera

• US 20010026683A1
• Filed: 03/22/2001
• Published: 10/04/2001
• Est. Priority Date: 03/27/2000
• Status: Active Grant

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Kubo, Hiroaki, Yukawa, Kazuhiko, Morimoto, Yasuhiro, Butsusaki, Takeru
• Granted Patent: US 6,453,124 B2
• Time in Patent Office: Days
• US Class Current: 396/89
• CPC Class Codes: G02B 7/28 Systems for automatic generation of focusing signals
• CPC Class Codes: H04N 23/632 for displaying or modifying preview images prior to image capturing, e.g. variety of image resolutions or capturing parameters
• CPC Class Codes: H04N 23/672 based on the phase difference signals
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements

Abstract

At power-on, a digital camera starts to operate with a display unit off (state S1). At a subsequent half shutter press of a shutter button, a quick return mirror is flipped down and phase difference AF is performed with live view display off (state S3). At a subsequent full press of the shutter button, the digital camera enters an image capture operation. With a quick return mirror in the up position, a focusing lens is moved to its in-focus, front focus and rear focus positions, at each of which contrast in an AF area of predetermined partial portion of an image is obtained for comparison to select a position of the focusing lens with maximum contrast (state S4). Then, image data is obtained and recorded on a memory card (state S5). With the above processing, the digital camera can perform autofocusing, as circumstances demand, by a contrast AF method.

Claims

1. A digital camera comprising:

an image sensor for capturing a subject image;

a mirror movable between a first position to enter an optical path from an imaging optical system to said image sensor, and a second position to withdraw from said optical path;

a driver for driving said mirror;

a first detector for detecting an in-focus condition of said imaging optical system on the basis of an image signal from said image sensor;

a display for displaying an image signal obtained by said image sensor; and

a focus controller for when said display provides a display, controlling said driver to move said mirror to said second position and driving said imaging optical system according to a result of detection by said first detector.

2. The digital camera according to

claim 1

, wherein said display displays a live view image.

3. The digital camera according to

claim 1

, further comprising:

a second detector for detecting an in-focus condition of said imaging optical system by a phase difference method;

an operating member for display to turn off said display; and

a display controller for turning off said display upon operation of said operating member for display, wherein when said display controller turns off said display, said focus controller places said mirror at said first position and drives said imaging optical system according to a result of detection by said second detector.

4. The digital camera according to

claim 3

, further comprising:

an operating member for image capture being movable between a first operating position and a second operating position which is a further pressed position from said first operating position, wherein

when said operating member for image capture is at said first operating position, said focus controller drives said imaging optical system according to a result of detection by said second detector.

5. The digital camera according to

claim 1

, further comprising:

an optical viewfinder for allowing visual recognition of a subject when said mirror is at said first position.

6. A digital camera comprising:

an image sensor for capturing a subject image;

a mirror movable between a first position to enter an optical path from an imaging optical system to said image sensor, and a second position to withdraw from said optical path;

a driver for driving said mirror;

a first detector for detecting an in-focus condition of said imaging optical system on the basis of an image signal from said image sensor;

a second detector for detecting an in-focus condition of said imaging optical system by a phase difference method;

a selector for selecting either said first detector or said second detector; and

a driver controller for when said selector selects said first detector to detect an in-focus condition, controlling said driver to move said mirror to said second position and when said selector selects said second detector to detect an in-focus condition, placing said mirror at said first position.

7. The digital camera according to

claim 6

, further comprising:

a display capable of displaying a live view image; and

a display controller for turning on said display when said selector selects said first detector to detect an in-focus condition.

8. The digital camera according to

claim 7

, wherein when said display is turned off, said driver controller places said mirror at said first position.

9. The digital camera according to

claim 8

, wherein after actual image recording, said display controller restores a condition of said display to a condition immediately before said actual image recording.

10. The digital camera according to

claim 6

, further comprising:

an optical viewfinder for allowing visual recognition of a subject when said mirror is at said first position.

11. A digital camera comprising:

an image sensor for capturing a subject image;

a mirror movable between a first position to enter an optical path from an imaging optical system to said image sensor, and a second position to withdraw from said optical path;

a driver for driving said mirror;

a first detector for detecting an in-focus condition of said imaging optical system on the basis of an image signal from said image sensor;

a second detector for detecting an in-focus condition of said imaging optical system by a phase difference method;

an operating member for image capture being movable from a first operating position to a second operating position which is a further pressed position from said first operating position; and

a focus controller for when said operating member for image capture is at said first operating position, placing said mirror at said first position and driving said imaging optical system according to a result of detection by said second detector and when said operating member for image capture is at said second operating position, controlling said driver to move said mirror to said second position and driving said imaging optical system according to a result of detection by said first detector.

12. The digital camera according to

claim 11

, further comprising:

an optical viewfinder for allowing visual recognition of a subject when said mirror is at said first position.

13. A digital camera comprising:

an image sensor for capturing a subject image;

a mirror movable between a first position to enter an optical path from an imaging optical system to said image sensor, and a second position to withdraw from said optical path;

a driver for driving said mirror;

a first detector for detecting an in-focus condition of said imaging optical system on the basis of an image signal from said image sensor;

a second detector for detecting an in-focus condition of said imaging optical system by a phase difference method; and

a focus controller for after driving said imaging optical system according to a result of detection by said second detector with said mirror located at said first position, then controlling said driver to move said mirror to said second position and driving said imaging optical system according to a result of detection by said first detector.

14. The digital camera according to

claim 13

, further comprising:

an exposure controller for performing a predetermined computation of exposure to obtain a proper exposure value for image capture and exercising exposure control over said image sensor on the basis of said proper exposure value, wherein

said focus controller drives said imaging optical system according to a result of detection by said first detector after completion of the exposure control by said exposure controller.

15. The digital camera according to

claim 14

, wherein

said focus controller controls a drive of said imaging optical system according to a result of detection by said second detector, in parallel with the exposure control by said exposure controller.

16. The digital camera according to

claim 13

, wherein,

when a focal length of said imaging optical system is not less than a predetermined value, said focus controller drives said imaging optical system according to a result of detection by said second detector and then drives said imaging optical system according to a result of detection by said first detector.